NEVER MIND! I found the answer myself (US passport renewals)

I THOUGHT I knew the answer to this question, but now I'm not sure at all. How do I renew my US passport while I'm here in the UK?

Do I have to go in person to the embassy in London? Or do I mail my old passport back to the US with the application (which, to be honest, I'd rather not do)?

My US passport expires in July 2021, but I'm trying to plan in advance, since it takes so long to do anything these days.

I THOUGHT I knew the answer to this question, but now I'm not sure at all. How do I renew my US passport while I'm here in the UK?

Do I have to go in person to the embassy in London? Or do I mail my old passport back to the US with the application (which, to be honest, I'd rather not do)?

My US passport expires in July 2021, but I'm trying to plan in advance, since it takes so long to do anything these days.

https://uk.usembassy.gov/u-s-citizen-services/u-s-passports/

I THOUGHT I knew the answer to this question, but now I'm not sure at all. How do I renew my US passport while I'm here in the UK?

Do I have to go in person to the embassy in London? Or do I mail my old passport back to the US with the application (which, to be honest, I'd rather not do)?

Neither, actually.

You mail your passport to the US Embassy in London and then they send it to the US for processing. Once they receive it back in London, they will mail it back to you.

See here for how to apply:
https://uk.usembassy.gov/u-s-citizen-services/u-s-passports/renew-an-adult-passport/

Many thanks! I appreciate it.

From the link above:

How to Submit Your Application By Mail

DO NOT mail your application to the United States.

All applications submitted by mail are processed at the U.S. Embassy in London.

You may send your application by Royal Mail Special Delivery to the following address:

United States Embassy
Passport & Citizenship Unit
33 Nine Elms Lane
London
SW11 7US

To ensure safe return of your new passport please enclose a pre-paid (up to 500grams), self-addressed Royal Mail Special Delivery envelope. These prepaid envelopes can be purchased from any UK post office.

Alternatively, you can arrange for your application to be delivered to the Embassy and your passport returned to you after processing, by the courier service, DX. Information on this service can be found at https://www.dxdelivery.com/consumer/dx-services-for-us-embassy#book-service

Processing time is approximately three weeks.

I mailed my passport to the US Embassy for renewal last week.  They were a bit unclear on how long it would take, the page said three weeks but there seemed to be a COVID extra bit that said it could as long as they want. 

I mailed my passport to the US Embassy for renewal last week.  They were a bit unclear on how long it would take, the page said three weeks but there seemed to be a COVID extra bit that said it could as long as they want. 

  I got my passport today, roughly 10 or 12 days after sending my  old one.  Pretty good service.

  I got my passport today, roughly 10 or 12 days after sending my  old one.  Pretty good service.

That's because you're not in a hurry! 

  I got my passport today, roughly 10 or 12 days after sending my  old one.  Pretty good service.

That's good to know. I don't want to send off my US passport while my citizenship application is pending, just in case they need THAT specific document. I also don't want to have to confuse matters by having a different US passport (the renewed one) added to the mix. I'll just have to wait until my UK citizenship is approved.